New tools: query_paramfile and set_paramfile

[samsrabin]

Description of changes

usage: query_paramfile [-h] -i INPUT [-p PFT] [variables ...]

Print values of one or more parameters from a CTSM paramfile.

positional arguments:
  variables          Names of variables to query (space-separated)

options:
  -h, --help         show this help message and exit
  -i, --input INPUT  Input netCDF file
  -p, --pft PFT      Comma-separated list of PFT names to print (only applies to PFT-specific variables)

usage: set_paramfile [-h] -i INPUT -o OUTPUT [-p PFT] [--drop-other-pfts] [-v VARIABLES] [param_changes ...]

Change values of one or more parameters in a CTSM paramfile.

positional arguments:
  param_changes         Parameter changes to apply. Use nan to set to the fill value. E.g.:
                           param1=new_value1 pftparam=pft1_val,nan,... param3=nan

options:
  -h, --help            show this help message and exit
  -i, --input INPUT     Input netCDF file
  -o, --output OUTPUT   Output netCDF file. Must not already exist.
  -p, --pft PFT         Comma-separated list of PFTs to include (only applies to PFT-specific variables)
  --drop-other-pfts     Do not include PFTs other than the ones given in -p/--pft
  -v, --variables VARIABLES
                        Comma-separated list of variables to extract

Finishing up:

• Add/edit docstrings
• Add docs
• Test editing a 1-d parameter that's not PFT-dimensioned

Optional? We definitely want this functionality, but it doesn't necessarily have to be this PR.

• Modularize and test using individual parts.
• Handle multidimensional parameters

Specific notes

Contributors other than yourself, if any: None

CTSM Issues Fixed:

• Contributes to Add Python tool for changing parameters #3393
• Contributes to Add Python tool for querying parameter values #3394

Are answers expected to change (and if so in what way)? No

Any User Interface Changes (namelist or namelist defaults changes)? No

Does this create a need to change or add documentation? Did you do so? Yes; no.

Testing performed, if any:

• Lots of Python unit and system tests for the new scripts and supporting functions.
• New CIME SystemTest SETPARAMFILE (change a couple of parameters and run with the new paramfile) passes.
• clm_pymods